Electromagnet



c. l. HALL Ewcmbummrr April 15, 1947.

Filed May 2, 1944 Inventor: Chester I. Hall,

Fig.1.

His Attorney PM... Apr. 15, umv

OFFICE ELECTROMAGNET Chester H. Hall, Vischerl Ferry, N. Y., asaignor toGeneral Electric Company, a corporation of New York Application May 2,1944, Serial no. 533,688

3 Claims. (01. 175-336) My invention relates to electromagnets, moreparticularly to direct current electromagnets, and has for its object asimple, reliable and light weight electromagnet of this type.

In carrying out my invention in one form I provide operatingelectromagnet having an operating coil of low inductance coeflicient anda pivotal mounting for the armature of the-magnet including a grommetmade of a resilient material, such as rubber, by means of which thearmature is secured at one end to the magnet frame. I also provide arelatively long flexible spring having one end secured to the armatureand carrying on its other end a movable contact. This elongated springgives a more gradual buildup or pressure between the contacts after theyengage each other and thereby tends to obviate bouncing oi the movablecontact and arcing resuiting therefrom. I

For a more complete understanding of my invention reference should behad' to the drawing in which Fig. l is a perspective view of a contactorembodying my invention; Fig. 2 is a tragmentary side elevation view ofthe device 01 Fig. 1; Fig. 3 is a fragmentary view in section of aresilient mounting for one end of the armature; Fig. 4 is a view insection of a resilient armature support; Fig. 5 is an elevation view ofthe two halves of an interlock switch mounted on the contaetor, whileFig. 6 is a side elevation view of the interlock switch of Fig. 5 with apart broken away to show the interior.

Referring to the drawing, in one form. of my invention I provide asuitable supporting base or The electromagnet comprises a coil l2 whosediameter is substantially greater than its axial length, preferablyseveral times greater than its length as shown in the drawing for thepurpose of obtaining high speed of operation in both closing and openingof the contactor. The mag-- net core comprises a plate is made of magnetiron secured to the support It by suitable screws or bolts and havingits lower end as seen in the drawing provided with a transverselyextending portion It projecting outward from the support IE to a pointjust beyond the outer limits of the coil. On this portion 14 are twobrackets ll (only one of which is shown in the drawing) to which thelower end or the armature l8 comprising a plate of magnet iron issecured by means or two grommet-like members ii and it made of.

a resilient material and bolts l9 and 20 extending through the'grommetsand the bracket II. The members I! and I8 are made of a suitable rubberor rubber-like material, preferably neeprene.

As' shown in the drawing, the lower end of the armature has a widthwhich is about the same as the diameter of the coil and the two supportsIi and is are secured in spaced-apart apertures in its lower end. Asshown in Fig. 4, the grommet l1, and also the grommet ll, are providedwith a central hole 2| for thebolt IS in a cylindrical portion 22 whichextends through a hole 23 (Fig. 3) in the end supporting portion of thearmature and preferably is slightly larger than the hole so as to secureitself permanently therein. Also, the two circular flanges 24 and 25 ofthe grommet are formed with their outer edges closely spaced together asshown in Fig. 4, while at the point where they join, the cylindricalportion 22, they are spaced apart a distance substantially equal to thethickness of the armature l8. Thus, when the grommet is forced part waythrough the hole so that the cylindrical portion lies in the hole, theflanges of the grommet are spread apart as shown in Fig. 3 by thearmature between them and thereby by reason of their resiliency grip thearmature between them and secure the grommet to the armature. Thisconstruction will exclude dust and foreign matter. The bolts l9 and 2bare drawn up tightly thereby to compress somewhat the grommets and seemthe armature to the bracket 55. i

As shown, the bracket extends downward at an angle somewhat less than 90degrees with the core portion l4 whereby the armature is. caused toextend normally in non-parallel relation upwardly with respect to theplate l3 which position is the unattracted position of the armature. Thearmature is thus biased to this position by the resiliency oi the rubbersupporting grommets. It is additionally biased by means of a helicalspring 26 surrounding a supporting bolt alf axial length of the coil ofthe movable contact and consequent arcing e engaging, when atbetween thecontacts during the closing movelon the cell, the end of mans. nclricalcore portion 25:: in its upper end the armature is forked to to all}?plate 53. This type of provide two projections 38 and 39 which can be upmagneticlealrage utilised to operate suitable interlock switches onlyone which, 0, is shown. Stops for limithe movement of the armature toits limit ctsd. position are provided consisting of two ts extendingthrough the two portions 38 and v one of whicl'a, 4!, is shown, andprovided b heads against which the portions mature is in unattractedposit the pancake .ct advent ge t current uic ar than its a two casing ia. noldcd clcc wl'fcn identical together in reversed As shown, thesewith registering g thicknesses substantially led thickness of theremainc two parts when they are put r These portions, as indicated inFig. 4, at opposite ends of the two assembled parts,

1r, .uial to the coin members 6 and 47 each of which has witc contactson each side.

Also, each or" the two members is provided with semicircular depressionsor grooves 48 and 45 which when the parts are put together formapertures for a longitudinally movable switch member or plunger 50extending in a direction at right angles to the stationary contact facesthickness between each end of the bracket 32 and on the members 45 and41. The plunger 50, the armature, after which the screws 33 and 34 40which is mad of a molded electrically insulatare tightened, the upperend of the contact 3! ing material, extends through an aperture in an isgiven the desired contact wipe. The open D- electrically conductingcontact bridging member sitlon or air gap is adjusted by nuts 41.normally biased by a helical spring 52 toward Another adjustment of thespring for varythe right-hand, as seen in Fig. 4, against a flange ingthe force of the spring is provided by means 53 on the plunger. Theother end of the spring of a screw 35 extending through an aperture inrests against a flange 54 secured to the plunger. its lower end. Thus byturning this screw against On the opposite side of the flange 54 is ahelical the spring, it is bent toward the armature and spring 55 whoseother end surrounds a. short the force of the spring availableforcontact prestubular spring seat 56 on a member 51. This sure therebyreduced. The screw is held in admember 51 is provided with an apertureconcenjusted position by means of a lock member 35 trio with the springseat 56 through which the having an aperture fitting over the head ofthe plunger extends and the member 51 fits in a screw and having itslower end secured to the recess 58 provided for it in each of the twohalves. rmature by the screw 28c. Thus, when the two parts, as shown inFig, 5,

When the armature moves toward its attracted are folded over on eachother, the bridging memposition upon energization of the coil, themovber 5| cooperates with the contacts on one side able contact 3iengages the stationary contact of each of the members 46 and 41 and isbiased at some predetermined point in the movement against the contactsby the spring 52. This forms of the armature and before the armaturereaches a normally closed interlock switch. The switch its fullyattracted position. Thereafter the ar- 69 4G is secured to the supportIn by terminal bolts nature continues its movement to its attracted 59and 60 molded in the casings and connected position and thereby appliesa desired force electrically to the members 46 and 41 with the throughthe spring 31": to the movable contact 4 plunger 50 in position to beengaged by the pro- Eil ,and also wipes the movable contact over thejection 38 or 39 when the armature is moved to stationary contact. Afterengagement of the its attracted position whereby the switch is movablecontact with the stationary contact, the opened. armature and bracket 32continue their move- As shown inFig, 6, the interlock switch can mentand move away from the spring 30 which be converted easily into anormally open switch i thereby bent and caused to apply an increasbysimply reversing the bridging member 5|. The 8 press 130 he stationaryContact. he bridging member has its ends bent into laterally Sp i yreason 0:? its length, pro a displaced relation with the central portionsegradual increase in the pressure applied to the cured to the plunger50 these ends being on the movable contact after ts engagement With theleft-hand of this central portion as seen in Fig. 4. stationary contact.This gradual application of With the bridging member reversed to theposipressure is an advantage in preventing bouncing tion shown in Fig.5, it is turned through an angle one 44 and 45 respectively of 139degrees about an axis perpendicular to the plunger 50. The bridgingmember is held by the spring 55 in spaced relation with the stationarycontacts. Also, the bridging member is positioned as seen in Fig. 0n theright-hand side of flange 53 as is also the spring 52. The flange 53,and also flange 54, preferably is a metal. part provided with a slotinto which fits a portion of reduced size on the plunger whereby theflanges can be readily removed for disassembly of the parts when the twohalves of the casing are sepsi 1d dble electric conductor (it forms elecconnection between the contact and a A member 52 secured to the base Ch,e "i have shown a particular embodiment oi invention, it will beunderstood, of course, that do not wish to be limited thereto since manymodifications may be made, and therefore contemplate by the appendedclaims to cover 1 any such modifications as fall Within the true spiritand scope of my invention.

What I claim as new and desire to secure by Letters Patent oi the UnitedStates is:

1. An electromagnet comprising an operating coil, a magnet core memberfor said coil, an armature for said coil including a supporting portionprovided with a hole, a member made of resilient material extendingthrough said hole and provided with flanges on opposite sides of saidsupporting portion constructed and arranged to grip said supportingportion between them, said resilient member being provided with acentral aperture, a support for said armature, and a bolt member securedto said support extending through said aperture for compressing saidresilient member against said support thereby to secure said resilientmember and said armature to said support so that said armature is biasedby said resilientmember to its unattracted position away from said coil,said resilient member flexing upon energization of said coil to providefor movement of said armature to its attracted position about an axissubstantially at right angles to said bolt member.

2. An electromagnet comprising an operating coil, a magnet core for saidcoil, a transversely extending projection on said magnet core, an armature member having a supporting portion provided with a hole in oneend, a resilient member made of rubber-like material extending throughsaid hole and provided with two flanges on opposite sides of armatureconstructed and arranged to grips-aid armature between them, saidresilient member lwlng provided with a central aperture, a bolteaten-ding through said apes ture and secured to said projectioncompress ing said resilient member against said projection whereby saidarmature is secured to said projec tion and biased by said resilientmember to unattracted position away from said coil, said resilientmember flexing upon energization of said coil to provide tor movement ofsaid ture to its attracted position about an axis sub stantially atright angles to said bolt.

r in electroinagnet comprising an operating coil, a magnet core for saidcoil, transversely extent f projections on said magnet core, an .ner'iber provided with two holes end, a ber of resilient material ar t ugheach oi said holes and provided two race on opposite sides of said arrnature constructed and arranged to grip said ar mature between them, eachor said resilient mem hers being provided with a central aperture, 2.bolt extending through each of said apertures and secured to one of saidprojections, said bolts being provided with heads for compressing saidresilient members against said projections whereby said armature issecured to said projections, said projections and said resilient membersbeing constructed and arranged to bias said armature to its unattractedposition away from said coil, said resilient members flexing uponenergization of said coil to provide for movement of said armature toits attracted position about an axis substantially at right angles tosaid bolt.

CHESTER. I. HALL.

REFERENCES CITED The following references are of record in the

